In research with the potential to help study stars and
improve space navigation, scientists have successfully used
lasers to cool a cloud of lithium atoms sufficiently to
observe unusual quantum properties of matter. Although current
technology does not permit humans to travel to the stars,
scientists can create a simulated star laboratory on Earth.

The scientists, at Rice University in Houston, Texas,
successfully simulated and photographed the process by which
white dwarfs and neutron stars retain their size and shape, a
mechanism called Fermi pressure. White dwarfs and neutron
stars are dense, compact objects created when normal stars use
up their fuel, cooling and succumbing to the forces of
gravity.

"This not only increases our understanding of the basic
laws of nature, but also lays the foundation for the
development of far-reaching technologies for deep space
navigation," said Dr. Kathie Olsen, acting associate
administrator for Biological and Physical Research (BPR) at
NASA Headquarters, Washington, D.C.

Fermi pressure, named for Dr. Enrico Fermi, a Nobel
Laureate prominent for his contributions in nuclear physics,
has been theorized as the star stabilization mechanism that
keeps white dwarfs and neutron stars from collapsing further.
NASA's Hubble Space Telescope and Chandra X-ray Observatory
have observed such objects, but this is the first time Fermi
pressure has been directly observed in an Earth laboratory.
The research by the Rice team, led by Dr. Randall Hulet, was
conducted under a grant from NASA's Biological and Physical
Research Program through NASA's Jet Propulsion Laboratory,
Pasadena, Calif.

"Many quantum effects have been theorized in the past 70
years, but only in the most recent years have scientists been
able to create laboratory environments sophisticated enough to
systematically test them," said Dr. Mark Lee, BPR fundamental
physics discipline scientist. "We are really elated and proud
that this newly established NASA program has yielded results
of such high significance."

The successful observation of Fermi pressure in the
laboratory is the first step toward other advances, including
improvements in atomic clocks, the most accurate of
timekeepers. New clocks could be designed using these ultra-
cold atoms so that the atoms collide less frequently, which
would lead to even greater accuracy. More precise clocks would
help digital communications systems and improve deep space
navigation.

"Experimenting with Fermi pressure may also lead to the
creation of a new type of superfluid from lithium," said
Hulet, physics professor at Rice University. Superfluids, in
which atoms flow without friction, are quantum systems very
similar to superconductors, which have zero resistance to
electrical current flow. This new super-cold system of atoms
could provide scientists a new testbed for theories of
superconductivity and shows promise in solving some of the
world's energy problems.

Hulet's team cooled lithium to less than one-fourth of a
millionth of a degree above absolute zero. Absolute zero is
the point at which scientists believe there can be no further
cooling. At these ultra-low temperatures, the researchers were
able to view and photograph two stable lithium isotopes,
identical except for the number of neutrons they contain. They
were thus able to demonstrate the star-stabilizing pressure.
However, on Earth this type of research is hampered by
gravity. The microgravity environment on the International
Space Station, when it is completed, will eventually serve as
an ideal location to study the transition to a superfluid.

Hulet co-authored the quantum experiment paper, which
appears in the March 30 issue of the journal Science, with
Rice University post-doctoral scientist Dr. Andrew Truscott,
graduate students Kevin Strecker and Guthrie Partridge, and
Dr. William McAlexander, now with Agilent Laboratories, Palo
Alto, Calif. More information on the experiment and the BPR
Fundamental Physics Program can be found at the following Web
sites:

Hulet's research was funded by NASA, the Office of Naval
Research, the National Science Foundation, and the R.A. Welch
Foundation. JPL manages the Fundamental Physics in
Microgravity Research Program for NASA's Office of Biological
and Physical Research, Washington, DC. JPL is a division of
the California Institute of Technology in Pasadena.